Hi there,
Nanny does differ from a maid.
For nanny, my guess is more expensive than a maid (assume Philippino). I myself will go for maid as they are 24 hours serving you!!
I am quite lucky. Both of my maids are good to my kids. I entrusted all the household chores to them.
To look for a good maid, look for a reliable agency. Set your requirements clearly to them - how many years of working experiences in HK / what's the reason of not being offer another contract by previous employer, etc.
I normally insisted on choosing those having a track record of 4 yrs or more working experiences with ONE FAMILY. And then called up the ex-employers for references. Never take in those who refused to let you talk to their ex-emploters. They probably have something wrong.
The golden rule is "always treat the maids like your family members". They will then treat your babies well! Make them feel like at home!
Good luck,
Fafa